At the moment I'm sitting in a cottage in France (recovering from a cold, but that's another story), a land notorious for not being so vegan friendly except in the larger cities. The native cuisine is generally not vegan - even vegetable dishes often use things like dairy products or animal fats or stock in the cooking process, which can make things difficult. But if you are a vegan you probably know about this, and come prepared accordingly. (I think it's a lot easier for lacto-ovo vegetarians in France; you could live on the delicious bread and cheese.)
If you are going to Japan, you might think that being vegan would be a lot easier. Japanese cuisine has a reputation for using lots of vegetables, seaweed and other vegan-friendly products. There is even a particular kind of cuisine in Japan called sho-jin ryouri (精進料理）, a mostly vegan temple cuisine, with a long and highly regarded tradition.
But as a reader who emailed me recently found out, being a vegan in Japan is just as hard as it is in Europe.